Accurate knowledge of longitudinal vehicle velocity can be used to improve many vehicle dynamics control systems. For example, the Anti-lock Braking System (ABS) controller can maximize the braking force and minimize the stopping distance. However, the vehicle's longitudinal velocity is usually not available in production vehicles. Wheel speeds are used instead in many situations. But wheel speeds do not represent the vehicle's longitudinal velocity when excessive tire slip exists.
Several methods have been proposed to determine longitudinal vehicle velocity. Certain methods use wheel speeds and longitudinal acceleration to determine longitudinal vehicle velocity and, therefore, need compensation for sensor bias, changes of rolling radii of wheels, and longitudinal slip. It has also been proposed to use the global positioning satellite system (GPS) in vehicle velocity calculations. However, this method suffers from low bandwidth because common GPS receivers have less than 10 Hz update rate and it is too low for vehicle dynamics control applications.